SSD won't boot while in main drive bay.

I replaced my HDD with a Samsung 840 120gb SSD in my M14x r2, and moved my HDD to a caddy in the optical drive bay.

But, windows install said I couldn't install on the SSD. I rebooted and loaded up windows install again, and this time it couldn't see the SSD (Not even in diskpart). So I moved the SSD to the optical drive caddy and windows installed perfectly fine. When I put it back into the primary bay, I get a disk read error. What am I doing wrong? this is the second SSD I've tried with the same problem, so it's not a faulty SSD. Am I missing something obvious?

How do I get my laptop to recognise the SSD when it's in the main drive bay?

notes:
I'm in AHCI
BIOS = A12

 

Make sure you go into your BIOS and have LEGACY boot on.

 

LEGACY is on.

 

Try this article. I would recommend setting it on RAID.

 

I know how to install Windows. It's a hardware problem. I contacted customer support and they said they won't help because I didn't buy the SSD off Dell. So, won't be dealing with Dell again..

Even though it's not an issue with the SSD itself

 

I thought that article had the instructions to reinstall Windows and load the IRST driver during the installation. That's what I would recommend you to do. Put the BIOS in RAID and load the IRST driver using a USB key. You will need to extract it in the root folder. After loading the driver the SSD should appear in the list of devices. Have you tried putting the old HDD back in PORT 1 just to make sure it's working fine?

 

Does your computer recognize the device at all?
Go to computers and devices and see if it's there first.